Many of the improvements in farm tractors are related to safety or to convenience of operation. This invention deals with both. It is an improvement in roll-over protection structures relating to the manner in which they are used.
Roll-over protection structures (or "bars") are strong generally U-shaped structural members secured to a vehicle on either side of the driver' position and extending overhead. The purpose of such devices is to protect the driver in the event of an accident, particularly an accident in which the vehicle rolls over or in which a heavy object falls on the vehicle. Roll-over protection structures are well-known in the prior art and have been used on farm tractors.
On occasion, roll-over protection structures can interfere with certain operations in which there is low overhead clearance. Because of this, some roll-over protection structures have been made adjustable. However, on large vehicles such as farm tractors, for which roll-over protection structures must be quite heavy, manipulating a roll-over protection structure between lowered and raised positions is difficult and inconvenient.
Adding hydraulic or other power equipment to move the roll-over protection structure may be an unsatisfactory answer, because of the complexity, space, and high cost involved. There is a need in tractors for an improved adjustable roll-over protection structure. It is this need which is addressed by this invention.